CoatingsPro Magazine

JUL 2018

CoatingsPro offers an in-depth look at coatings based on case studies, successful business operation, new products, industry news, and the safe and profitable use of coatings and equipment.

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Page 56 of 68

56 JULY 2018 COATINGSPROMAG.COM of the roofing panels and the cut ends of the girts — as well as any punched holes or other modifications — were left uncoated, and the steel began to corrode, and with rain water added, the staining of the white surfaces quickly began. e panels being stacked and stored horizontally allowed the rainwater to pond and stain the coated surfaces. e typical industrial coating norms and detailed specifications were not the norm in this construc- tion process where many of the procedures seem to have fallen under "typical construction standards" or the infamous " industry standards." In considering the materials selection, performance expectations, and responsibilities of installing the primer coating on structural steel, the following is commentary from the Metal Systems Building Manual, MBMA: 4.2.4 Structural Framing Shop Primer, "It is common industry practice for metal building manufacturers to use SSPC Paint Specification No. 15 for primer used on primary and secondary structural members. A ll structural members of the Metal Building System not fabricated of corrosion-resistant materials or protected by a corro- sion-resistant coating are painted with one coat of shop primer. A ll surfaces to receive shop primer are cleaned of loose rust, loose mill scale, and other foreign matter by using, as a minimum, the hand tool cleaning method SSPC-SP-2 prior to painting. e manufacturer is not required to power tool clean, sandblast, flame clean, or pickle. e coat of shop primer is intended to protect the steel framing for only a short period of exposure to ordinary atmospheric conditions. e coat of shop primer does not provide the uniformity of appearance, or the durability and corrosion resistance of a field-applied finish coat of paint over a shop primer. Pre-painted material may be used at the manufacturer's option, provided the pre-painted coating provides protection equal to or greater than that provided by the shop primer. e manufacturer is not responsible for the deterioration of the primer or corrosion that may result from exposure to atmospheric and environmental conditions, nor the compatibility of the primer to any field-applied coating. Minor abrasions to the shop coat caused by handling, loading, shipping, unloading, and erection after painting are unavoidable. Any touch-up painting of these minor abrasions is the responsibility of the end customer. Primed steel, which is stored in the field pending erection, should be kept free of the ground, and so positioned as to minimize water-holding pockets, dust, mud, and other contamination of the primer film. Repairs of damage to primed surfaces and/or removal of foreign material due to improper field storage or site conditions are not the responsibility of the manufacturer." Generally, that commentary places the onus on the end customer and not the manufacturer. W hile it can be argued who the end user actually is, be it the contractor or the owner, and where the repair responsibility falls, ultimately the manufacturer is absolved of responsibility per the above commentary. is typical construction process probably has a lot to do with why red oxide is typically chosen as the primer color. Any corrosion and staining from corrosion would not be as apparent on the red oxide as it is on a white-primed surface. So what was the path forward, and Staining on Structural Steel Girts exhibiting edge corrosion and staining Corrosion and staining evident on the ceiling joists and roofing panels

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